Given the task definition and input, reply with output. In this task, you are given a question. You have to answer the question based on your information.

Jonkheer Douwe Sirtema van Grovestins (Leeuwarden, Brussels, 1710 – February 26, 1778) was a Frisian courtier at the court of which stadtholder, that was the first hereditary Stadtholder of all the United Provinces?

William IV, Prince of Orange-Nassau